Coffee roasting apparatus



18 Sheets-Sheet 1 AUg 6, 1968 H. l.. SMITH, JR

COFFEE ROASTING APPARATUS Original Filed Jan. l5, 1965 Nm met?.

Aug. 6, 1968 H. L. SMITH, JR y3,395,634

COFFEE ROAST ING APPARATUS original Filed Jan. 15,' 1965 18 Sheets-sheetz INVENT OR HOF/16E L. SMITH, J?.

Aug. 6, 1968 H. L. SMITH, JR

COFFEE ROASTING APPARATUS Original Filed Jan. l5, 1965 18 Sheets-Sheet 5Aug. 6, 1968 H. L. SMITH, JR 3,395,634

COFFEE HOAST ING APPARATUS Original Filed Jan. l5, 1965 18 Sheets-Sheet4 il?. 5 .El -5- --|6 INVENT OR HGRACE l.. SMH/1, JR

Aug. 6, 196s H. L. SMITH, JR 3,395,634

COFFEE ROASTING APPARATUS Original Filed Jan. 15, 1965 18 Sheets-Sheet 5INVENT OR HORACE L5M/Th; JR

INVENTOR 18 Sheets-Sheet 6 Aug. 6, 1968 original Filed Jan. 15, 196sHORACE I.. SMITH, JR.

ug. 6, 1968 H. L. SMITH, JR 3,395,634

COFFEE ROASTING APPARATUS original Filed Jan. 15, 1965 18 Sheets-Sheet 77 INVENTOR HORACE L. sfu/TH, .//z

Aug. 6, 1968 H. L. SMITH, JR

COFFEE ROASTING APPARATUS 18 Sheets-Sheet 8 Original Filed Jan. 15, 1965INvENroR hon/:cf L. swr/v, ./R.

Aug. 6, 1968 H. SMITH, JR

COFFEE ROASTING APPARATUS 18 Sheets-Sheet 9 Original Filed Jan. 15, 1965Original Filed Jan. l5, 1965 H. L. SMITH, JR

COFFEE ROASTING APPARATUS PURGE GAS msPERsER 222 Hof @As FROM COMMERCIALN H x RoAsTaNG um'r 233 LEGEND:

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18 Sheets-Sheet lO Aug 6, 196s H. L. SMITH, JR 3,395,634

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COFFEE ROASTING APPARATUS Original Filed Jan. l5, 1965 18 Sheets-Sheet1:2

LI4O- START 'L'a'z STOP M MT A' .PRESSuRIzE `\SI54 START A' STOP MT' I-MHI T7 REAcToR `\SI45 LL `*i I MM M START STOP 1 FF PRESSURE \s|46MooULATING A AUTOMATIC PSI PRESSURE SWITCH SET To OPEN AT M ALL MANUAL5o RSI.

MT TIMED MANUAL T TEMPERATURE CONTROLLED REACTOR INVENT OR HORACE L..9M/TH, JR.

Aug. 6, 1968 H. sMrrH, JR 3,395,634

COFFEE ROASTING APPARATUS Original Filed Jan. l5, 1965 18 Sheets-Sheet13 STOP START l 4 M MANUAL A AUTOMATIC Aug. 6, 1968 H. L. SMH, JR3,395,634

COFFEE ROAST ING APPARATUS Original F'iled Jan. 15, 1965 18 Sheets-Sheet14 scRuaeeR ooMPREssoR Lam \2ao AccuMuLAToR REACTOR INVENT OR HORACE L.SMITH, JR

Aug. 6, 1968 H. l.. SMITH, JR

COFFEE ROASTING APPARATUS original Filed Jan. 1s, 1965 18 Sheets-Sheetl5 INVENTOR lio/PAGE L sfu/TH, .1R

U8- 6, 1968 H. l.. SMITH, JR

COFFEE RASTING APPARATUS Original Filed Jan. 15

18 Sheets-Sheet 16 INVENTOR HoRAcE L. 9M/TH, ./R.

H. l.. SMITH, JR

COFFEE ROAST ING APPARATUS Original Filed Jan. 15, 1965 18 Sheets-Sheetl? Aug. 6, 1968 H. l.. SMITH, JR 3,395,634

COFFEE ROASTING APPARATUS Original Filed Jan. l5, 1965 18 Sheets-Sheet18 l." f o CHARGING 3'0 HoPPER ERoM AccuMuLAToR 346 344 3 Q 35o HEATER,4 34s 347i; 3'2 REAcToR 339 BoosTERI 32a AccUMu- 343 LAToR 345 4/ 38o370 374 358 'V 376 73 354 HEAT 37| -'LT ExcHANGER/ 356 330 MAIN 3M`shs^g`- cooLER A BoosTER|f366 332 372 336 .1. 4 l TRANSFER -390 36 .368coMPREssoR 33|- 334 FROM AccUMuLAToR lNERT GAS DISCHARGE GENERATORHOPPER INVENTOR United States Patent O 3,395,634 COFFEE ROASTINGAPPARATUS Horace L. Smith, Jr., Richmond, Va., assignor to HuppCorporation, Cleveland, Ohio, a corporation of Virginia Originalapplication Jan. 15, 1965, Ser. No. 425,702, now Patent No. 3,345,180,dated Oct. 3,1967. Divided and this application Sept. 7, 1966, Ser. No.577,673

17 Claims. (Cl. 99-236) ABSTRACT OF THE DISCLOSURE Apparatus fortreating particulate solids including at least one pressurizable,isolatable reaction vessel and a closed circulation system for atreating uid which may include a chaff separating and collecting system,an arrangement for varying the flow rate and temperature of the fluidsupplied to the reaction vessel, an arrangement for venting the vesselin which vessel pressures are equalized to minimize stresses on internalcomponents, and an arrangement for separating evolved volatiles fromrecirculated treating fluid together with an inert gas generator, ifdesired.

This application is a division of application No. 425,702, led lan. 15,1965, for Coffee Roasting Method, now Patent No. 3,345,180.

This invention relates to novel improved fluid-solids 1 contactapparatus.

For the most part, the principles of the present invention will bedeveloped by relating them to the roasting of coffee and the like2 asthis specific application is the most important commercially at thepresent time and as, in another specific aspect, this invention relatesto novel improved apparatus for roasting coffee and other similarproducts. It is to be understood, however, that the present inventionis, in its broader aspects, of far lgreater utility; and the ensuringdiscussion of the invention is therefore intended to be illustrative andnot limiting with regard to the broader aspects of the invention, whichis defined only by the appended claims.

One of the primary objects of the present invention is to provide novelimproved apparatus for contacting iluids and solids.

The foregoing and other important objects of this invention areaccomplished by utilizing a novel reaction vessel which can bepressurized and in which a bed of the solids to be treated is iluidizedand continuously rotated 3 during the iluid treatment cycle. A number ofadvantages result from fluidizing and continuously circulating thesolids while they are being contacted with the treating iluid as willbecome apparent shortly.

Both iluidized beds and beds in which there is a continuous movement ofthe solids have heretofore been employed in apparatus for treatingsolids with gases and fluids. Exemplary apparatus employing iluidizedbeds are disclosed in U.S. Patents Nos. 2,212,120, issued Aug. 20,

1 The terni fluid is used generically herein tocenconipass gases,mixtures of gases, and other materials with similar t'low properties.

2 Other typical applications of the present invention include theroasting of other food products such as cocoa beans and nuts and themanufacture of expanded food products such as putfed cereals andpopcorn. The present invention may also be used for drying cereal grainsor other particulate solids and for effecting a wide variety of chemicalreactions commonly carried out in uidized beds. In short, the presentinvention is applicable to virtually all processes involving the contactof fluids with particulate solids.

3 The term duidized rotating bed will be employed to described a bed ofsolids which is iuidized and in which the solids continuously circulatein paths (shown in FIGURE 7) in which the solids move upwardly in theperipheral regions of the reaction vessel, inwardly in the upper part ofthe bed, downwardly in the inner region of the reaction vessel, andoutwardly in the lower part of the bed.

1940, to R. D. Kneale et al. for Method of Roasting Coffee; 2,857,683,issued Oct. 28, 1958, to F. Schytil for Coffee Roaster; and 2,859,116,issued Nov. 4, 1958, to E. Heimbs et al. for Treatment of Coffee andOther Materials. Exemplary of the patents disclosing apparatus in whichthere is circulation of the solids being treated are U.S. Patents Nos.2,437,694, issued Mar. 16, 1948, to C. N. Hickman `for Method forBlending Powder Grains; 2,689,973, issued Sept. 28, 1954, to L. V. Leeet al. for Method and Apparatus for Contacting Solids With Gases; and2,786,280, issued Mar. 26, 1957, to P. E. Gishler et al. for Method ofContacting Solid Particles With Fluids; and German Patent No. 1,064,789,issued Sept. 3, 1959, to H. Bach for Vorrichtung fr Aromaver'besserungund Stabilisierung von Rstkaffee.

The present invention differs from anything disclosed in the prior artin that there is both iluidization and rotation of the bed of solids. Inaddition, the pattern of circulation or rotation differs from that whichoccurs in the prior art apparatus. Specifically, all of the.above-identified patents disclosing beds in which there iS circulationof the lparticles are concerned with what are known as spouted beds inwhich the solids are moved upwardly in a small spout in the center ofthe -bed by the treating fluid and migrate downwardly in the remaining,major, outer portion of the bed. This contrasts directly with thepresent invention in which, as mentioned above, the solids move upwardlyin the peripheral regions of the bed and downwardly in its innerreaches. In other words, in the fluidized rotating bed of the presentinvention, the particles of solids circulate in a 4manner directlyopposite that to which they circulate in a spoute-d bed.

The uidized rotating bed of the present invention has important.advantages over both the fluidized and spouted beds of the prior art as`was indicated previously. First, in the present invention, there is amaterially more uniform treatment of the solids because of thecontinuous rapid turnover of the solids in the fluidized rotating bed.In iluidized beds the solids are practically stagnant; and the treatingfluid changes characteristics (for example, cools) as it passes upwardly4through the bed. Consequently, the treatment given the solids in theupper part of the bed may vary widely from the treatment of the solidsin the lower reaches of the bed; and different particles of the treatedproduct -may therefore have radically different characteristics.

Solids treated by spouted bed techniques may also contain particles ofwidely varying characteristics because there is an extremely slowturnover of the `solids due to the sluggish downward migration of thesolids in all but the central spout of a spouted bed. This is -becausethe area of the spout is necessarily very small in comparison to thetotal area of the bed. As the nonspouted areas of the bed contain a verylarge part of the solids and as the volume of the solids moving downwardin the nonspouted part of the bed cannot exceed the volume of solidsmoving upwardly in the spout while maintaining the stability of the bed,the downward migration of the solids is necessarily very slow. Moreover,spouted Abeds are subject to short-circuiting, which even furtherincreases nonuniormity of the treated product.

A second important advantage of the present invention is that it is-niuch more versatile than anything heretofore known including apparatusutilizing -uidized and spouted beds. For example, the :reaction vesselmay be maintained at pressures varying from atmospheric pressure (orless than atmospheric pressure) to several hundred pounds per squareinch without upsetting the uidization or rotation of the bed of solids.Similarly, for a -given pressure, the mass rate of flow of the treatingyfluid oan be varied over wide limits without adversely effectingfluidization or rotation of the solids. Also, other parameters such asthe composition and temperature of the treating uid can be varied asdesired for particular applications with` out Aadverse effect.

A third advantage of the present invention over fluidized and spoutedbed and other prior art techniques is that the solids treatment can bemore accurately controlled because of the intimate and uniformuid-solids contact provided. This is extremely important in many, if notmost, processes utilizing duid-solids contact.

A further advantage of the present invention in roasting and otherapplications where the solids are heated by the treatin-g fluid is thatthere is a substantially higher rate of heat transfer from the treatingfluid to the solids than in prior art apparatus because of the ffuidizedrotating bed and because the reaction vessel is pressurized. Thismaterially reduces processing time and, therefore, production costs. Inaddition, in many applications of the present invention, the decreasedprocess time and pressurized fluid treating environment reduce the lossof vola tile constituents or otherwise beneficially effect the solids.Therefore, in many such applications, the techniques of the presentinvention provide a treated product which, in comparison to productsobtainable by prior art techniques, has materially improved quality orother improved characteristics, Analogously, the reduction in processtime, treatment under pressure, and the versatility of the presentinvention provide materially higher yields in many applications of theinvention, making the present invention more economical than apparatusutilizing prior art techniques.

Another advantage of the present invention is that power requirementsare minimized because there is only a small pressure drop (typicallyless than or slightly above 1.5% of t-he system pressure) in thetreating fiuid as it passes through the reaction vessel.

Another important advantage of the present invention is that it can bereadily employed where the particle size of the solids to be treated istoo large to be fluidized in the conventional manner. As pointed out inthe Gishler patent mentioned above, it is extremely difficult tofiuidize particles having a size greater than 20 mesh and entirelyimpracticable to fluidize particles as large as grains of wheat byconventional techniques. By employing the principles of the presentinvention, however, beds of much larger particles--coffee beans, forexample-can be readily fluidized and rotated.

The present invention also has a further advantage over spouted bedtechniques in that a much larger bed of solids can be treated. As apractical matter, a spouted bed cannot be more than a few inches indiameter. As the width of the bed is increased, the diameter of the,spout must be increased or the downward migration of the solids in thenon-spouted portions of the bed will be so sluggish as to render theprocess useless. However, the power required to produce spoutingincreases much more rapidly than spout diameter; and, if the diameter ofthe spout is greater than a very few inches, the power required toproduce it in other than a shallow bed of no practical utility iseconomically impracticable. Also, spouts in extremely shallow beds or inbeds more than `a few inches in diameter are unstable. This factor makesit further impracticable to produce spouted beds which are sufficientlylarge for use on a commercial scale.

From the foregoing, it will be apparent that further important objectsof the present invention include the provision of novel improvedfluid-solids contact apparatus:

(1) Which is applicable to a wide variety of processes involvingfluids-solids contact;

(2) In which the bed of solids to be treated is fluidized andcontinuously rotated by the treating fluid;

(3) Which is capable of producing a more uniform final product and/or ahigher quality product or one with better characteristics than hasheretofore been obtainable;

(4) Which is capable of producing a more rapid turnover of the particlesbeing treated than has heretofore been possible; Y v

(5) Which is more versatile than the prior art apparatus for producingfluid-solids contact;

(6) In which the treatment of the solids can be more accurateliIcontrolled than has heretofore been possible;

(7) Which, when the solids are heated, provides a higher rate of heattransfer from the treating fluid to the solids than heretofore employedtechniques;

(8) Which materially reduces the time required to effect a giventreatment;

(9) Which is capable of handling solids of larger particle size than theapparatus of the prior art; and

(l0) In which it is practicable to treat a larger bed of solids than canbe treated by spouted bed and similar prior art techniques.

Another important specific object of this present invention is theprovision of novel improved apparatus which incorporates the novelfluid-solids techniques discussed above and is particularly adapted forcoffee roasting and similar applications.

Roasting coffee by employing the fluid-solids Contact techniquesdescribed above has a number of advantages. These include increasedyields and a roast which is more uniform, has a higher percentage ofextractibles (typically on the order of 10% higher), and a higherpercentage of total solids in the cup.

The advantage of increased yields and a more uniform roast areself-evident.

The higher percentages of total extractib'les is of considerableeconomic importance in the manufacture of instant coffee in that theyield of instant coffee from unroasted beans is a direct reflection ofthe total extractibles in the roasted coffee. Therefore, use of thepresent invention decreases the cost of producing instant coffee.

The higher total solids content provided 'by the present invention isalso important because the quality of brewed coffee is directly relatedto the total solids content of the roasted beans. Therefore,`coffeeroasted in the apparatus of the present invention makes a better cup ofcoffee than the same coffee roasted by other techniques.

Another extremely important advantage of the present invention in theroasting of coffee is that, because of its versatility and the closecontrol over the roasting process it provides, it materially reduces theloss of desirable volatiles and, at the same time, makes it possible todrive off undesirable volatile components from the beans. As a result,cheap low grade coffees roasted in accord with the present invention canbe upgraded to a quality equal to that of expensive beans roasted by theprocesses heretofore employed. Consequently, the present inventionprovides a material economic advantage over both the prior art processesfor producing coffee for grinding and for producing instant coffee'because the major cost factor in producing coffee of both types is thecost of the coffee itself.

Another important advantage of roasting coffee in accord with theprinciples of the present invention is that the flexibility andversatility of the present invention makes it readily adaptable Ito theroasting of all `types of coffee beans, a versatility which heretoforeknown coffee roasters do not possess.

From the foregoing it will be apparent that further specific andimportant objects of the present invention include the provision ofnovel improved coffee roasting appara-tus which, in contrast to thatheretofore available:

(l) Produces increased yields;

(2) Produces a more uniform roast and a more uniform final product;

(3) Produces a higher total solids content in the roasted coffee;

(4) Produces a higher percentage of total extractibles in the roastedcoffee;

